Blood group test to determine a person’s blood type. The test is important, if one need a blood transfusion or planning to donate blood. All the blood group are not compatible and because of that it is important to know the blood group. Blood grouping may also be done to see if two people have any blood relation. Blood type is determined by what kind of antigens the red blood cells have on the surface. Antigens are substances that help our body to differentiate between its own cells and outsider or foreign cell. If the feels that the cell is foreign, it will set out to destroy it. ABO and the Rh antigen are the most important antigens which are either present (positive, +) or absent (negative, -). So the two most common blood type tests are the ABO and Rh tests. ABO blood typing system groups the blood into one of four categories:

Type A has the A antigen

Type B has the B antigen

Type AB has both A and B antigens

Type O has neither A nor B antigens

How the blood donation works? Once blood enters the human body with antigens that one does not have, body will create antibodies against it. As long as the blood one receive doesn’t have any antigens that mark his/ her body as foreign, their bodies won’t attack it. In other words, donations work as follows:

O: Type O individuals can donate blood to anyone (because their blood has no antigens), but can receive blood only from other type O individuals (because blood with any antigens is seen as foreign).

A: Type A individuals can donate to other type A individuals and type AB individuals. Type A individuals can receive blood only from other type A individuals and type O individuals.

AB: Type AB individuals can give blood only to other AB individuals, but can receive blood of any type.

Blood types are future organized by Rh factor:

Rh+: People with Rh-positive blood have Rh antigens on the surface of their red blood cells. People with Rh+ blood can receive Rh+ or Rh- blood.

Rh-: People with Rh-negative blood do not have Rh antigens. People with Rh- blood can receive only blood that is also Rh-.

Together, the ABO and Rh grouping systems yield your complete blood type. There are eight possible types: O+, O-, A+, A-, B+, B-, AB+, and AB-. While type 0 negative has long been considered a universal donor, new research findings suggest that that additional antibodies are sometimes present and may cause serious reactions during a transfusion.